1. Field of the Invention
The present invention generally relates to a touch sensing display panel, and more particularly, to a capacitive touch sensing display panel.
2. Description of Related Art
In recent years, along with the rapid developments of the various applications of information technology, wireless mobile phones and information household appliances, to achieve the goals of more convenient usage, more compact design and more humanized features, many information products have changed their input devices from traditional keyboard or mouse to touch sensing display panel. In terms of the sensing methodology, in general, touch sensing display panels can be roughly categorized into resistive type, capacitive type, optical type, acoustic type and electromagnetic type. Taking a capacitive touch sensing display panel as an example, based on the driving and the sensing manner, the capacitive touch sensing display panel can be further divided into self capacitive touch sensing display panel and mutual capacitive touch sensing display panel.
A conventional self capacitive touch sensing display panel includes a plurality of first electrode series extending along the X-axis direction and a plurality of second electrode series extending along the Y-axis direction, wherein the X-axis direction is different from the Y-axis direction. When a human's finger touches the above-mentioned self capacitive touch sensing display panel, the touched electrode in the panel functions for both sensing and driving.
FIGS. 1A and 1B are respectively a localized cross-sectional diagram and a top-view diagram of a conventional mutual capacitive touch sensing display panel. Referring to FIGS. 1A and 1B, a conventional mutual capacitive touch sensing display panel 100 includes a substrate 110, an opposite substrate 120, a display medium layer 130, a touch sensing substrate 160, a plurality of first electrode series 140 extending along the X-axis direction and a plurality of second electrode series 150 extending along the Y-axis direction, wherein the X-axis direction is different from the Y-axis direction. The first electrode series 140 includes a plurality of first electrodes 142 and the second electrode series 150 includes a plurality of second electrodes 152. It should be noted that the first electrode series 140 and the second electrode series 150 are fabricated by using different thin film deposition and etching processes.
FIG. 1C is a diagram showing the usual electric field lines generated by an electrode and FIG. 1D is a diagram showing the electric field lines generated by an electrode touched by a conductor. When a person touches the mutual capacitive touch sensing display panel 100 with a finger, the parasitic capacitance of the finger and the parasitic capacitance of the touched sensing electrode are equivalently connected in series to each other, which results in changing the capacitance between the first electrode 142 and the second electrode 152. By delivering the changed signal to a controller, the coordinates of an instantly touching point can be derived. Since the first electrode series 140 and the second electrode series 150 are fabricated by using different thin film deposition processes, so that when a user manipulates the above-mentioned mutual capacitive touch sensing display panel 100, the inconsistent transmittances caused respectively by the first electrode series 140 and the second electrode series 150 and the phenomenon of decreased transmittances can be easily observed.
In this regard, how to improve the transmittance uniformity on the entire frame of a capacitive touch sensing display panel and to promote the transmittance thereof has become one of the projects for the manufacturing of a touch sensing display panel to be solved today.